The recommendation regarding tuna was immediately attacked as inadequate by a member of the FDA advisory panel that addressed it. University of Arizona toxicology professor Vas Aposhian resigned from the panel, saying the advisory did not reflect the experts' view that children and childbearing women should not eat albacore tuna, and should eat less light tuna than the advisory recommends.

The federal agencies issued the advisory about albacore tuna (which is generally more expensive) while also listing low-mercury fish that can be eaten more frequently -- including shrimp, canned "light" tuna, salmon, pollock and catfish. The advisory recommended eating as much as 12 ounces (or two average meals) of these fish per week. According to the FDA, fish sticks are largely made from pollock.

The foundation said that about 78 percent of tuna sold in the United States is the lower-mercury "chunk light" variety of skipjack tuna. "Solid white" albacore makes up about 22 percent of the $1.3 billion domestic tuna market. The albacore variety, which foundation officials say can always be identified by labels on the can, may have three times as much mercury -- because the fish are older and have consumed more from the environment.